Currently, physical distribution is being carried out over longer distances and on a more international scale than before, where transportation of larger-sized and higher-precision articles is on the rise. As is well known, cases and containers storing articles to be transported are used in various distribution processes. Typically used are paper cardboard boxes, but in recent years, there have been increased occasions when cases or containers made from plate materials such as synthetic resin cardboard are employed.
Synthetic resin cases and containers are popularized mainly because they can be repeatedly used to provide a cost advantage and reduce environmental burdens, and can be easily subjected to technical development in pursuit of improved durability and weather-resistance, higher strength, material recycling, antistatic and antimicrobial properties, and so on.
At present, there are proposed various transport cases and containers of this type that can be folded to make them less bulky in repeatedly using them after transportation (that is, in using them as returnable boxes) (refer to Patent Documents 1 and 2). In addition, there is proposed an assembly container that can be separated into plate materials and stacked on a pallet (Patent Document 3).    Patent Document 1: Japanese Utility Model Publication No. 4-214738    Patent Document 2: Japanese Unexamined Patent Publication No. 6-211240    Patent Document 2: Japanese Unexamined Patent Publication No. 2002-255165